 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.console;

 import java.lang.reflect.Field ;

 import org.eclipse.core.expressions.EvaluationContext;
 import org.eclipse.core.expressions.EvaluationResult;
 import org.eclipse.core.expressions.Expression;
 import org.eclipse.core.expressions.ExpressionConverter;
 import org.eclipse.core.expressions.ExpressionTagNames;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.variables.VariablesPlugin;
 import org.eclipse.ui.IPluginContribution;
 import org.eclipse.ui.console.ConsolePlugin;
 import org.eclipse.ui.console.IConsole;
 import org.eclipse.ui.console.IPatternMatchListenerDelegate;

 import com.ibm.icu.text.MessageFormat;

 public class PatternMatchListenerExtension implements IPluginContribution {

     private IConfigurationElement fConfig;
     private Expression fEnablementExpression;
     private String fPattern;
     private String fQualifier;
     private int fFlags = -1;
    
     public PatternMatchListenerExtension(IConfigurationElement extension) {
         fConfig = extension;
     }

     /*
      * returns the integer value of the flags defined in java.util.regex.Pattern.
      * Both <code>Pattern.MULTILINE</code> and <code>MULTILINE</code> will return
      * the same value.
      */
     public int parseFlags(String flagsElement) {
         int val = 0;
         if (flagsElement == null) {
             return val;
         }
             
         try {
             flagsElement = flagsElement.replaceAll("Pattern.", ""); //$NON-NLS-1$ //$NON-NLS-2$
 String [] tokens = flagsElement.split("\\s\\|\\s"); //$NON-NLS-1$
 Class clazz = Class.forName("java.util.regex.Pattern"); //$NON-NLS-1$

             for (int i = 0; i < tokens.length; i++) {
                 Field field = clazz.getDeclaredField(tokens[i]);
                 val |= field.getInt(null);
             }
         } catch (ClassNotFoundException e) {
             ConsolePlugin.log(e);
         } catch (NoSuchFieldException e) {
             ConsolePlugin.log(e);
         } catch (IllegalAccessException e) {
             ConsolePlugin.log(e);
         }
         return val;
     }
     
     public boolean isEnabledFor(IConsole console) throws CoreException {
         EvaluationContext context = new EvaluationContext(null, console);
         EvaluationResult evaluationResult = getEnablementExpression().evaluate(context);
         return evaluationResult == EvaluationResult.TRUE;
     }
     
     public IPatternMatchListenerDelegate createDelegate() throws CoreException {
         return (IPatternMatchListenerDelegate) fConfig.createExecutableExtension("class"); //$NON-NLS-1$
 }
     
     public Expression getEnablementExpression() throws CoreException {
         if (fEnablementExpression == null) {
             IConfigurationElement[] elements = fConfig.getChildren(ExpressionTagNames.ENABLEMENT);
             if (elements.length == 0) {
                 String message = MessageFormat.format("{0} " +getLocalId() + " {1} " + getPluginId() + " {2}", new String [] {ConsoleMessages.PatternMatchListenerExtension_3,ConsoleMessages.PatternMatchListenerExtension_4,ConsoleMessages.PatternMatchListenerExtension_5}); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 ConsolePlugin.log(new Status(IStatus.WARNING, ConsolePlugin.getUniqueIdentifier(), IStatus.OK, message, null));
             }
             IConfigurationElement enablement = elements.length > 0 ? elements[0] : null;

             if (enablement != null) {
                 fEnablementExpression = ExpressionConverter.getDefault().perform(enablement);
             }
         }
         return fEnablementExpression;
     }
     
     /*
      * returns the regular expression to be matched.
      */
     public String getPattern() {
         if (fPattern == null) {
             fPattern = fConfig.getAttribute("regex"); //$NON-NLS-1$
 try {
                 fPattern = VariablesPlugin.getDefault().getStringVariableManager().performStringSubstitution(fPattern, false);
             } catch (CoreException e) {
                 ConsolePlugin.log(e);
             }
         }
         return fPattern;
     }

     /*
      * returns the flags to be used by <code>Pattern.compile(pattern, flags)</code>
      */
     public int getCompilerFlags() {
         if(fFlags < 0) {
             String flagsAttribute = fConfig.getAttribute("flags"); //$NON-NLS-1$
 fFlags = parseFlags(flagsAttribute);
         }
         return fFlags;
     }
     
     /* (non-Javadoc)
      * @see org.eclipse.ui.IPluginContribution#getLocalId()
      */
     public String getLocalId() {
         return fConfig.getAttribute("id"); //$NON-NLS-1$
 }

     /* (non-Javadoc)
      * @see org.eclipse.ui.IPluginContribution#getPluginId()
      */
     public String getPluginId() {
         return fConfig.getContributor().getName();
     }

     public String getQuickPattern() {
         if (fQualifier == null) {
             fQualifier = fConfig.getAttribute("qualifier"); //$NON-NLS-1$
 try {
                 if (fQualifier != null) {
                     fQualifier = VariablesPlugin.getDefault().getStringVariableManager().performStringSubstitution(fQualifier, false);
                 }
             } catch (CoreException e) {
                 ConsolePlugin.log(e);
             }
         }
         return fQualifier;
     }
 }

